Recently, people have a considerable interest in manned space flight projects and space life science relating to the projects.
A human mission to Mars takes about two and a half years to return to earth, and when a human body is exposed to the space environment for a long period of time, the biological tissues are considerably changed, which may influence missions in the space. For example, the bone, one of the important tissues of a human body, decreases in bone mineral density by about 1% a month, so it may cause a severe problem when a human stays in space for a long period of time.
Accordingly, it is required to take a counterpart that can minimize adverse influences on a human body under microgravity in a space environment in order to successfully proceed with space projects.
Many studies using a 3D-clinostat, for example in US Patent Application Publication No. 2005-028650 A1, have been made to study influences under a space environment, but there is little experiment apparatus capable of performing a study about a countermeasure against adverse influences under the space environment, that is, microgravity. In those apparatuses, there is no apparatus capable of estimating a loss in musculoskeletal system of a human body and taking a countermeasure against the loss.